Elevated Temperature Mechanical Properties of a Directionally Solidified NiAl/Cr(Mo)-Hf Alloy
The microstructure of directionally solidified (DS) NiAl-28Cr-5Mo-1Hf eutectic alloy was investigated by SEM and TEM. The eutectic alloy is composed of NiAl matrix , Cr (Mo) phase and a small amount of Heusler phase. Tensile testing of this alloy was performed from room temperature to 1373K. The brittle-to-ductile transition temperature (BDTT) is dependent on strain rate, with two orders of increase on strain rate resulting in a100K increase in transition temperature. The observation of fracture surface showed that at temperature above BDTT, the fractograph changes from NiAl cleavage and debonding along NiAl/Cr(Mo) interface boundary to ductile in nature.
Young-Jin Kim, Dong-Ho Bae and Yun-Jae Kim
C. M. Xu et al., "Elevated Temperature Mechanical Properties of a Directionally Solidified NiAl/Cr(Mo)-Hf Alloy ", Key Engineering Materials, Vols. 297-300, pp. 1477-1481, 2005